Abrasive head



Nov, 4, 1947. E. H. BRADLEY 2,430,099

ABRASIVE HEAD Filed July 2, 1945 ABRASIVE HEAD v Filed July 2, 1945 2Sheets-Sheet 2 INVENTOR. fK/VA-SI' Bmw 11 Patented Nov. 4,1947

- i Ernest 11. Bradley, Indianapolis, Ind., assignor to Vonnegut MoulderCorporation, Indianapolis,

Ind., a corporation Application Ju y 2, 1945, Serial No. 602,749 12Claims. (01. 51-194) This invention relates to an abrasive head of thetype that may be employed in smoothing products of wood and othermaterials, including mouldings, carvings, die castings and the like,

having irregular surfaces, and particularly a spindle sander of thecharacter disclosed in Letters Patent to Plengemeier No. 2,125,460,granted August 2, 1938. The invention further pertains to that part ofthe abrasive head comprising the anchorage for the abrasive strips.

In abrasive heads of this character it may be desirable to employ arelatively large number 01' brushes which are closely spaced and betweeneach of which an abrasive strip extends, as com! pared with the sandershown in the above patent.

To develop such an abrasive head, two problems had to be overcome;namely, the brush holders so constructed and related\ as to permit thegreatest number of brushes to be removably mounted in the head in asclosely spaced relation as possible, and without materially increasingthe cost and weight. This is accomplished by a simplified structureherein disclosed wherein the brush holders comprise a series of U-shapedFig.3 is a front elevation or the head assembled for use with the coverplate removed.

Fig. 4 is a perspective view of the anchor loop structure showing indotted lines a portion or the abrasive strip as secured thereto.

Fig. 5 is a central vertical section through the head with partsremoved.

In the drawings there is illustrated an abrasive or polishing unithaving a supporting base l0 upon which there is mounted an electricmotor i l driven from any suitable source of current, not illustrated.Extending from the motor there is a bearing housing i2, and such housingmay extend from both sides of the motor to provide dual abrasive units.v Driven by the motor and supported by the bearing housing there is aspindle l3 for supporting and rapidly rotating the abrasive head.

.The abrasive head comprises an annular back plate It about theperiphery of which there is an annular series of outwardly extending bruh holders I5 slightly spaced from each other and secured perpendicularlyto the back plate. Said holders are rigidly and permanently secured tothe back plate and are U-shaped in cross section or in the form ofchannels which may be die cast or preferably stamped from sheet metal.Said brush holders open outwardly and radially with .respect to thespindle l3 upon which the back the confines of the inner spool, andwhereby the plurality of wings. each of which accommodates and issecured to an abrasive strip. .Thus, within limits, any number ofabrasive strips may be conveniently anchored by one pin.

The full nature of the invention will be 'understood from theaccompanying drawings and the following description and claims:

Fig. 1 is a perspective view of the abrasive head mounted in positionfor the sanding operation.

Fig. 2 is a perspective view of the head with parts removed.

' tend the iullwldth of the head with the fibres or I plate It is lockedfor rotation therewith. The side walls of the holders are angledslightly toward each other to provide a restricted slot or opening forslidably're'ceiving and retaining the respective brushes [8.

The brushes l6 primarily serve the purpose of flexibly backing up theabrasive strips and exbristles thereof, extending radially outwardly.-

The fibres of the brushes are clamped in the usual manner near theanchor'end of the brush to form a compact base I! which may be encasedwith a metalstrip, said base ll being of a'form and size to convenientlyslide endwise into the respective holders [5 and be anchored therein bythe side walls forming the restricted opening or slot. By means of thisconstruction the brushes may be readily assembled'and removed from thehead, and due to the holders being formed of a series of U-shapedchannels to slidably receive the respective brushes, any desired numberand spacing of such holders may be provided to accommodate the desirednumber of abrasive strips and brushes.

Surroundingthe spindle II there is a plurality of pins It for anchoringthe abrasive strips.

. n 3 Baid pins are spaced from and about the shaft in parallel relationthereto and to each other. By reason of the anchoring arrangement of theabrasive strips it becomes necessary only to provide one anchoring pinfor a group of strips and their backing up brushes l8. Anchored by thepins I8 there is provided an abrasive strip l9 for each opening betweenthe holders l arranged to extend outwardly to lie adjacent theirrespective brushes. Said strips are wound upon each other to form a rollabout the spool comprising the anchor pins l8. Thus, as the abrasivestrips are used or worn out, they may be partially unrolled from aboutthe spool so as to bring a new portion into use, the used portion beingclipp d off.

After the brushes It have been slipped into place in their respectiveholders and the abrasive strips ll anchored to the pins I8, as shown inFig. 3, the cover plate or. cap is locked to the spindle to extendthereover. The cover plateis provided on its inner surface with aseating ring 20a having spaced depressions 28b arranged to engage andinterlock with the ends of the anchor pins 18. Also about its innerperipheral surface,

1 iiTiaprovided with means, such as the annular bead 20c havinginterlocking engagement with notches formed in the adjacent ends of theholders I5. Thus with the cover plate '28 secured on the spindle, theholders l5 and pins l8 are locked in operative position.

In order that a comparatively few pins l8 may accommodate a largernumber of abrasive strips and brushes, the anchored ends of the stripsare arranged in multiple. Thus, as shown in Fig. 3, for example, thereare thirty-two brushes and abrasive strips, whereas there are only eightpins. This is accomplished by providing a fabric anchor loop 2| formedto be slid over the free endsof the respective anchor pins. As hereinillustrated, theanchor loop is formed from a plurality of sheets ofgummed fabric grouped and folded intermediate their ends so as to bestitched, riveted or otherwise secured as indicated at 22 to provide thelooped portion and outwardly flared wing portions 23. Each of the saidwing portions is arranged for attachment to one or more abrasive strips,either by adhesive, as herein shown, stitching or clamping in anydesired manner. With the anchor loop mounted about one of the anchorpins, any desired multiple of the abrasive strips maybe embodied in theroll to extend through a corresponding number of slots adjacent thebrush holders and their respective brushes.

This arrangement permits of complete freedom in respect to the number ofbrushes and abrasive strips employed without regard to the number ofanchoring pins or the limited space in which they are mounted. It alsopermits of convenient handling and assembling of the abrasive stripswith their anchor loops which may be provided in packaged groups readyto be slipped into position on the anchor pins with the individualstrips 4 and collar, with the pins I 8, are free to rotate relative tothe holders l5.

The collars 25 and 28 are each provided with a bore 30 to receive awrench pin. By thus holding collar 25 and the brush holders stationarywhen the nut 21 is loosened, and rotating collar 29 relative thereto,plate 20 and pins l8 may be turned to reel up the abrasive strips orpermit them to be unreeled and drawn outwardly to present new abrasive.suriaces.

The invention claimed is:

1. An abrasive head including a predetermined number of outwardlyextending brushes spaced from each other about the periphery thereof, a.plurality of abrasive strips rolled upon each other within said headwith the free end ofat least one of said strips extending outwardlybetween adjacent brushes, a. support for said brushes, an

annular series of anchor members less in number than said brushes andabrasive strips carried by said support inwardly of and concentricallywith said brushes to provide a, spool and anchor for the inner ends oi.said strips, and a connecting element secured to a plurality of saidstrips.

adapted to interlock with each of said anchor members.

2. An abrasive head including a predetermined number or closely spacedbrush supporting holders, an annular back plate for supporting saidholders about the outer edge thereof to extend perpendicularly thereto,each of said holders being generally U-shaped in cross section toprovide a.

channel with a restricted opening for slidably receiving the base of anoutwardly extending brush, the base of each brush being pinched to slidelongitudinally of said holder and interlock with the walls thereofagainst outward displacement, a plurality of abrasive strips rolled uponeach other within said head with the free end of at least one of saidstrips extending outwardly between adjacent holders, an annular seriesof anchor members less in number than said holdders and abrasive stripsrotatably carried by said base plate inwardly of and concentrically withsaid holders to provide a spool and anchor for the inner ends of saidstrips, and a connecting element secured to a plurality of said stripsadapted to interlock with each of said anchor members.

3. An abrasive head including a predetermined from each other about theperiphery thereof, a, plurality of abrasive strips rolled upon eachother within said head with the free end of at least one of said stripsextending outwardly between adjacent brushes, a support for saidbrushes, an annular series of anchor pins less in number than saidbrushes and abrasive strips rotatably carried by said support inwardlyof and concentrically with said brushes to provide a spool and anchorfor the inner ends of said strips, and means for anchoring a, pluralityof said strips to each of said anchor pins comprising a looped sheetadapted to be slidably mounted over each of said anchor pins formed withwing for connection with the inner ends of the respective abrasivestrips.

4. An abrasive head including a predetermined number of closely spacedbrush supporting holders, an annular back plate for supporting saidholders about the outer edge thereof to extend perpendicular thereto,each of said holders being generally U-shaped in cross section toprovide a channel with a restricted opening for slidably receiving thebase of an outwardly extending brush. the base portion of each brush forthe inner ends of said strips, and a looped fabric adapted to be,slidably mounted over each of said anchor pins formed with wings forconnection with the inner ends of a plurality of abrasive strips,whereby a plurality of said strips may be anchored to one of said pins.7

5. An article of manufacture comprising a sheet of flexible materiallooped intermediate its ends to receive an anchor pin therein, and meansfor securing the looped portion of said sheet to provide a plurality offreely extending wing portions for attachment to the anchored ends of aplurality of abrasive strips.

6. An article of manufacture comprising a'sheet of flexible materiallooped intermediate-its ends to receive an anchor pin therein, means forsecuring the looped portion of said sheet to provide a plurality offreely extending wing portions, and means on each of said wing portionsfor attaching the end of an abrasive strip thereto.

7. In an article of manufacture, a plurality of abrasive strips, ananchor therefor comprising a fabric sheet looped intermediate its endsto re ceive an anchor pin therein, means for securing the loopedportions of said sheet to provide a plurality of freely extending wingportions, and means for attaching an abrasive strip to each of said wingportions.

8. In an abrasive head having an annular series or brushes spaced fromeach other and a lesser number of anchor pins mounted inwardly thereoffor anchoring a greater number of abrasive strips, at least one stripfor each brush, an anchor for said strips comprising a sheet of flexiblematerial looped intermediate its ends to receive an anchor pin therein,means for securing the looped portion of said sheet to provide aplurality of freely extending wing portions, and means for sive stripsthan anchor pins, at least one strip for each brush, an anchor for saidstrips comprising a sheet of material looped to receive one of saidanchor pins therein and having a plurality of free wing portionsextending outwardly therefrom, and means for securing the end of anabrasive strip to each of said wing portions.

10. An article of manufacture comprising a sheet of flexible materiallooped intermediate its ends to receive an anchoring element therein,and means for securing the looped portion of said sheet to provide anoutwardly extending wing portion for attachment to the anchored ends ofa plurality of abrasive strips.

11. An article of manufacture comprising a sheet of flexible materiallooped intermediate its ends to receive an anchoring element therein,means for securing the looped portion of said sheet to provide anoutwardly extending wing portion, and a plurality of abrasive stripseach having its anchored end secured to said wing portion. /g g 12. Anarticle of manufacture comprising a sheet of fiexlblmafterial foldedover upon itself to form an anchor receiving loop, the folds of saidsheet being secured together adjacent the loop to provide an outwardlyextending wing portion, and a plurality of abrasive strips each havingits anchored end secured to said wing portion. ERNEST H. BRADLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 564,587 Black July 28, 18962,194,577 Yonnegut Mar, 26, 1940 1,978,681 MacGregor Oct. 30, 19342,125,460 Plengemeier Aug. 2, 1938

